Author 
Exponential VCA... some math 
CLee 
...very little math actually, but I'm checking my math for an exponential VCA
IF: The VCA has an 80db dynamic range and a 05v CV with 5v being 0db/unity gain. And a 10v p/p signal at the input.
These would be the p/p readings for the output at various CV INs
5v CV = 10v out, 0db
4v CV = 1.5v out, 16.2db
3v CV = 0.24v out, 32.4db
2v CV = 0.037v out, 48.6db
1v CV = 0.0057v out, 64.8db
0v CV = 0.001v out, 80db
All of my VCAs have been linear, so I guess I'm looking for confirmation that these would be correct readings and this is expected behavior.


guest 
close, but it should be 16dB steps, and not 16.2dB steps. the PP voltages would need to be recalculated as well.


CLee 
guest wrote:  close, but it should be 16dB steps, and not 16.2dB steps. the PP voltages would need to be recalculated as well. 
Thanks guest. I was rounding when I said 80db.
V2164 is 33mv/db and my 0 to 5v CV is scaled to 2.7v giving me 2.7/.033=81.8db. If I divide the 81.8db by 5v I actually get 16.8db/volt (not the 16.2 I stated). I think I rounded to 81 for some reason and then divided to get db/volt.
But in general I was hoping for some confirmation on the basic response. I'm not used to exponential VCAs and was a little surprised at how much change happens within a single volt.


guest 
yes, the general format is correct. and it should change a lot at the beginning.


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